These studies represent a continuation of our previous work in the fields of experimental diabetes, pregnancy and islet-cell-transplantation. They are intended to explore the effectiveness of the fetal pancreas transplantation model in providing an in utero environment consistent with normal fetal development. Specific organ systems to be studied include the adenohypophysis, the pancreas, adrenal glands and the lungs. Utilizing techniques of immunoassay, ultrastructural analysis, immunocytochemistry and quantitative morphometry, the morphological as well as biochemical changes in these fetal organs will be analyzed in relation to the severity of maternal diabetes and in relation to the degree of reversal of the diabetic state attained by transplantation. In addition, the effects of pregnancy on the acute and chronic stability of the transplanted state (reversal of diabetes) will be examined.